Models / Phi 4 ReasoningID: azure_ai/Phi-4-reasoning
reasoning model by Microsoft

Phi 4 Reasoning

Phi-4-reasoning is Microsoft's 14-billion parameter reasoning model specialized in step-by-step logical deduction, STEM proofs, and rigorous code verification.

Certified & verified by nRouter· facts checked 2026-09-16 against 2 official sources

PlaygroundQuick Start
Context window16.4K
Max output4K
Maker

Microsoft

Served On

Azure Foundry

Specifications

Context window, ranked against other reasoning models

Proportional scale: 0 to 1.05M tokens. Not ranked, no published context window: gpt-5.5-pro, gpt-5.6-cyber.

Context window

16.4K

Source: learn.microsoft.com
Max output

4K

Source: learn.microsoft.com
Modality

reasoning

Vision
Function calling
System prompt

Benchmarks

specialized reasoning model pending arena text leaderboard evaluation

Pricing

Rates are read live

Pricing for Phi-4-reasoning is fetched from the live catalogue on load, so it is never served from a cache that could outlive a repricing.

Availability

Not enough data yet

We have not collected enough health probes for this model to publish an uptime or latency figure. A percentage from a handful of samples is fabricated precision, so none is shown until the sample count supports one.

How Phi 4 Reasoning is billed

Billed at the provider's list price, with no per-token markup.

Exact list price
Tokens settle at the published rate of the model that served your call.
Cache discounts passed through
Provider prompt-caching discounts reach your balance with no added fee.
Cost on every response
Each response carries the x-nr-request-cost header, so you can reconcile spend per request.

More from Microsoft

Phi-4-multimodal-instructPhi-4Phi-4-mini-instructPhi-4-mini-reasoning

Start building with Phi-4-reasoning

One API key, three steps. Choose your tool to begin.

  1. Get a key

    Create API key

  2. Set your API key

    export NROUTER_API_KEY="<YOUR_API_KEY>"

  3. Configure Claude Code

    Choose a tool, then copy its setup from the panel.

npm install -g @anthropic-ai/claude-code
Claude Code · azure_ai/Phi-4-reasoning
# Point Claude Code to nRouter gateway
export ANTHROPIC_BASE_URL="https://api.nrouter.ai"
export ANTHROPIC_API_KEY="$NROUTER_API_KEY"

# Launch with azure_ai/Phi-4-reasoning
claude --model azure_ai/Phi-4-reasoning